DS8870 architecture and rack layout

The practice shell is a G10 DS8A50, not a DS8870, but it’s good for the skill that matters on any generation, which is turning list output into a picture of the rack. After that you’ll fill in a DS8870 rack map by hand.

Practice shell note: the practice shell is our teaching tool, not IBM software. Real DS CLI output looks very much like this but is not identical. All outputs below are real shell output from a G10 system; card slot numbers are the shell’s own. Messages starting with SIM are practice shell messages.

1Reset and list the I/O enclosures

Run this:

python ds8sim.py -cfg lab.profile
simctl reset
lsioenclosure -s

You should see this:

dscli> simctl reset
SIM0100I simctl: factory state restored (users and passwords kept; use simctl reset -all to reset them too).
dscli> lsioenclosure -s
Date/Time: 24 October 2026 19:59:07 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
IBM.1400-1B1-78SV0
IBM.1400-1B2-78SV0
IBM.1400-1B3-78SV0
IBM.1400-1B4-78SV0

The middle part, 1B1 to 1B4, is the I/O enclosure (bay) name. A DS8870 base frame uses the same names for the four I/O enclosures at the bottom of its main column, and 1B5 to 1B8 for the four in the first expansion frame.

✅ Checkpoint: Four enclosures, 1B1 to 1B4.

2See which cards sit in which enclosure

Run this:

lshacard
lsdacard

You should see this:

dscli> lshacard
Date/Time: 24 October 2026 19:59:07 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
ID                           I/O enclosure      Frame State  Type  Speed   Fibre Channel ports Encryption capable Location code         S/N
==================================================================================================================================================
IBM.1400-1B1-78SV0/R-1-P1-C1 IBM.1400-1B1-78SV0 1     Online FC-LW 32 Gb/s 4                   yes                U1400.1B1.78SV0-P1-C1 YH10SV0001
IBM.1400-1B2-78SV0/R-1-P1-C3 IBM.1400-1B2-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B2.78SV0-P1-C3 YH10SV0003
IBM.1400-1B2-78SV0/R-1-P1-C4 IBM.1400-1B2-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B2.78SV0-P1-C4 YH10SV0004
IBM.1400-1B3-78SV0/R-1-P1-C5 IBM.1400-1B3-78SV0 1     Online FC-SW 32 Gb/s 4                   yes                U1400.1B3.78SV0-P1-C5 YH10SV0005
dscli> lsdacard
Date/Time: 24 October 2026 19:59:07 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
ID                           I/O enclosure      Frame State  DA pair Location code         S/N
=====================================================================================================
IBM.1400-1B1-78SV0/R-1-P1-C6 IBM.1400-1B1-78SV0 1     Online 0       U1400.1B1.78SV0-P1-C6 YA30SV0010
IBM.1400-1B2-78SV0/R-1-P1-C6 IBM.1400-1B2-78SV0 1     Online 0       U1400.1B2.78SV0-P1-C6 YA30SV0020
IBM.1400-1B1-78SV0/R-1-P1-C8 IBM.1400-1B1-78SV0 1     Online 2       U1400.1B1.78SV0-P1-C8 YA30SV0012
IBM.1400-1B2-78SV0/R-1-P1-C8 IBM.1400-1B2-78SV0 1     Online 2       U1400.1B2.78SV0-P1-C8 YA30SV0022

Read the Location code from the end: P1-C3 is card slot C3 in enclosure 1B2. Each DA pair has one card in 1B1 and one in 1B2, the same pairing rule a DS8870 follows, with one DA of the pair in each enclosure of an I/O enclosure pair.

Now look at the HAs. 1B2 holds two and 1B4 holds none, while on a DS8870 the Redbook rule is one HA in every I/O enclosure before a second goes in any of them. Keep that in mind for Step 4.

✅ Checkpoint: Two DA pairs (0 and 2), each split over 1B1 and 1B2; four HAs over three enclosures.

3Fill in a DS8870 rack map by hand

Close the drawing above. On paper, sketch the base frame of an Enterprise Class DS8870 with a narrow left column and a wide right column, and fill in each numbered position from top to bottom.

✅ Checkpoint: At least eight of nine positions right.

4Turn the list output into a map with Python

This script runs on your laptop in the lab folder next to ds8sim.py, not on the DS8000. It calls the DS CLI three times, prints one line per I/O enclosure and then checks the HA spreading rule. It uses the auto.profile from Lesson 22, so if you don’t have one yet, set it up as shown there.

File bays.py:

# Runs on your workstation or jump server, not on the DS8000.
# It talks to the DS8000 only through the DS CLI (auto.profile: banner off, header on, format delim).
import csv, subprocess
DSCLI = ["python", "ds8sim.py", "-cfg", "auto.profile"]   # at work: ["dscli", "-cfg", "auto.profile"]

def dscli(*args):
    """Run one DS CLI command and return its rows as dictionaries."""
    out = subprocess.run(DSCLI + list(args), capture_output=True, text=True).stdout
    lines = [l for l in out.splitlines() if l and not l.startswith("SaatVedha") and not l.startswith("CMUC")]
    return list(csv.DictReader(lines))

bays = {}                                   # "1B1" -> {"HA": [...], "DA": [...]}
for e in dscli("lsioenclosure", "-l"):
    bays[e["ID"].split("-")[1]] = {"HA": [], "DA": []}
for card in dscli("lshacard", "-l"):
    bay, slot = card["I/O enclosure"].split("-")[1], card["Location code"].split("-")[-1]
    bays[bay]["HA"].append(slot)
for card in dscli("lsdacard", "-l"):
    bay, slot = card["I/O enclosure"].split("-")[1], card["Location code"].split("-")[-1]
    bays[bay]["DA"].append(f"{slot} (DA pair {card['DA pair']})")

print("I/O enclosure map")
for bay, cards in sorted(bays.items()):
    print(f"  {bay}: HA {', '.join(cards['HA']) or '-':10} DA {', '.join(cards['DA']) or '-'}")

# Rule from the Redbooks: one HA in every I/O enclosure before a second HA in any enclosure
counts = {bay: len(c["HA"]) for bay, c in bays.items()}
if max(counts.values()) > 1 and min(counts.values()) == 0:
    empty = [b for b, n in counts.items() if n == 0]
    full = [b for b, n in counts.items() if n > 1]
    print(f"WARN: {', '.join(full)} has 2+ HAs while {', '.join(empty)} has none. Spread host adapters first.")
else:
    print("OK: host adapters are spread over the I/O enclosures.")

Run this (in the lab folder):

python bays.py

You should see this:

I/O enclosure map
  1B1: HA C1         DA C6 (DA pair 0), C8 (DA pair 2)
  1B2: HA C3, C4     DA C6 (DA pair 0), C8 (DA pair 2)
  1B3: HA C5         DA -
  1B4: HA -          DA -
WARN: 1B2 has 2+ HAs while 1B4 has none. Spread host adapters first.

Take that warning seriously. If 1B2 is serviced or fails, every host port in it goes away at once, so when you plan the next HA, put it in 1B4.

At work you’d run the same script against each DS8000 before a hardware order, so nobody ends up buying a card for the wrong bay.

✅ Checkpoint: The script prints four bays and the WARN line for 1B2 and 1B4.